The recent rapid enhancement in the resolution of camera modules has made it difficult to increase the accuracy of components in accordance with the enhancement in the resolution. Thus, an assembly process for the camera modules requires highly accurate adjustment of the optical axis between an optical imaging lens and an image sensor. Moreover, mobile applications require a reduction in height of the camera modules. Thus, the height and size of the components of the camera modules have been reduced, and such reduction is ongoing.
PTL 1 to PTL 3 each disclose a method for highly accurately assembling a camera module by adopting a configuration of a lens barrel without screws. However, according to this assembly method, a sensor cover is provided between the image sensor and the imaging lens, and therefore, a space corresponding to the sensor cover is required. Thus, the assembly method may not meet the recent demand for the reduction in height of the camera module.
Moreover, a method for adjusting the position of the imaging lens in an optical axis direction is known. However, enhancement in resolution of the image sensor requires not only the adjustment in the optical axis direction but also adjustment of the angle of tilt of the imaging lens. Thus, PTL 4 and PTL 5 each propose a method for adjusting the optical axis of the imaging lens on the basis of imaging information captured by the image sensor.
This method for adjusting the optical axis of the imaging lens on the basis of the imaging information captured by the image sensor is referred to as active alignment. The use of the active alignment enables provision of a high-quality camera module with a satisfactorily adjusted angle between an imaging lens and an image sensor (sensor). PTL 4 discloses an adjustment algorithm and also an adjustment method for adjusting the angle between an imaging lens and an image sensor. The adjustment method disclosed in PTL 4 is a method for adjusting the angle between the image sensor and an actuator in which the imaging lens is incorporated. This adjustment method is currently used in many processes.